Hydrogenation of unsaturated alcohols



Patented Sept. 22, 1936 HYDROGENATION 0F ALCO UNSATURATED HOLS Herbert P. A. Groll and James Burg-in, Oakland,

Calif., assignors-to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing.

15 Claims.

This invention relates to a process for the production. of saturated alcohols from the readily rearrangeable unsaturated alcohols of monoand poly-olefinic character which possess an unsaturated tertiary carbon atom linked to a carbinol group, said process comprising reacting such an unsaturated alcohol with hydrogen, in the presence of a'hydrogenation catalyst, while avoiding excessive conditions of hydrogenation at which substantial rearrangement of the unsaturated alcohol would occur.

An object of this invention is to provide a practical andeconomical method for the technicalscale production of saturated alcohols which have a wide variety of uses for which the corresponding unsaturated alcohols are unsuitable.

The unsaturated alcohols possessing an unsaturated tertiary carbon atom linked to a carbinol group cannot be substantially converted to the corresponding saturated alcohols by any of the known methods of efiecting hydrogenation of unsaturated alcohols. The unsaturated alcohols possessing such a structural arrange ment are, on contact with the usual hydrogenation catalysts under conditions at which hydrogenation would occur at a substantial rate, substantially completely rearranged to their saturated isomers. 'As a consequence of this behavior, no process has been provided 'for hydrogenation of this active group of unsaturated alcohols, and the same have hitherto not been hydrogenated.

the principles of our invention, the members of this class of unsaturated alcohols to which the same is applicable, can be substantially completely hydrogenated while substantially avoiding rearrangement. Our process comprises selecting a hydrogenation catalyst of such activity that the hydrogenation can be efiected at a practical rate under conditions of temperature and pressure at which rearrangement of the unsaturated alcohol is substantially avoided. In other words, if a catalyst of suitable initial activity is selected, the process is executed under conditions of temperature, pressure and contact time favorable to rapid hydrogenation, while the same conditions are not conducive to rearrangement.

The unsaturated alcohols which may be bydrogenated in accordance with the present in- Application March 25, 1935, Serial No. 12,910

and at least one carbinol group.- The unsaturat f ed alcohol will comprise an iso-alkyl chain containing an unsaturated tertiary carbon atom,"

which chain may or may not be attached to a cyclic radical as of the aromatic, alicyclic and heterocyclic series. Although the invention is particularly concerned with unsaturated alcohols containing primary and/or secondary carbinol.

groups, the same is also applicable to those containing one or more tertiary carbinol groups.

A particularly suitable group of unsaturated alcohols includes those of mono-olefinic character possessing at least one of the grouping l regardless of the character of the organic compound in whichrsuch a groupingmay be contained. The loose bonds of the above grouping may be taken up by hydrogen atoms and/or by alkyl, alkoxy, aralkyl, aralkoxy, carbocyclic, heterocyclic and/or othersuitable organic radicals which may or may not be further substituted, or the loose bonds may be taken up by suitable inorganic substituents. The loose bonds may also be taken up by carbinol groups and/or hydroxyl radicals, however, it is understood that anhydroxyl radical may not be linked to an unsaturated carbon atom or to a carbonatom already containing a hydroxyl radical. Generally, we do not desire to execute our invention with unsaturated alcohols containing sulphur, phosphorous or' halogen atoms, due to the fact that the presence of these elements in a free or combined form may detrimentally influence the life and activity of the hydrogenation catalyst employed.

In executing our invention with poly-olefinic unsaturated alcohols, we prefer to employ those containing the same number of olefinic double bonds and carbinol groups, each carbinol group of which is linked to an unsaturated tertiary carbon atom. It is, however, to be understood that other polyolefinic alcohols are also contemplated, provided that they containat least one unsaturated tertiary carbon atom linked to a carbinol group. Thus it is to be understood that un- CHFC-CHIOH,

' OCH cm-o-onon-c=cm,

' H; om

and the like as well as their homologues, analogues and suitable substitution products.

The source of the unsaturated alcohol to be treated is immaterial. Such alcohols or mixtures thereof maybe prepared by any of the known methods. A desirable mode of preparing suitable unsaturated alcohols on a technical scale comprises chlorination of tertiary olefines and subsequent hydrolysis of the resulting unsaturated chlorides.

In accordance with the principles of this invention, the hydrogenation is effected in the presence of a selected hydrogenation catalyst. The choice of a suitable catalyst will be dependent on its specific activity and on the specific activity of the treated alcohol and its stability against rearrangement under the conditions of temperature andpressure at which the reaction proceeds at a practical rate. The catalyst is generally chosen with respect to the unsaturated alcohol treated so as to permit substantial hydrogenation of the same at a substantial rate under conditions of temperature and pressure at which a minimum of undesirable side reactions such as rearrangement of the unsaturated alcohol can occur.

In the great majority of cases, excellent results may be obtained by employing the relatively inexpensive, readily prepared and easily regenerated base metal catalysts which possess the desired degree of activity. For example, metals such as copper, chromium, thallium, nickel, iron, cobalt and the like may be particularly active and eflicacious base metal catalysts when employed in a finely divided state or deposited on a suitable carrier. The term base metal is used to designate those metals which, in contrast to the noble metals, are oxidized to an appreciable extent on exposure to air. Pyrophoric nickel, iron and cobalt catalysts are particularly suitable for our purpose. They possess the desired initial activity which permits rapid hydro.- genation at relatively low temperatures and pressures and, in addition, the catalysts of this preferred group are readily prepared and regenerated and substantially retain their initial catalytic activity over relatively long periods of use.

The metallic catalysts may be prepared by any suitable method and employed severally or in combination. The catalysts are preferably preformed and employed per se or deposited upon an inert substance or carrier such as pumice, calcium carbonate, silica gel, charcoal and the like. The catalytic activity of a selected catalyst may be considerably enhanced by incorporating with it small quantities of other substances capable of acting as promoters. For example, in some cases, a catalyst more eflicacious than pure nickel may be obtained by adding small quantities of one or more suitable metal alkaline-acting agents to a precipitated nickel hydroxide before rflucing it to metallic nickel. Suitable promoters include high melting and difficultly reducible oxygencontaining compounds, in particular, the oxides and oxygen-containing salts of elements such as the alkaline earth and rare earth metals, beryllium, zinc, magnesium, aluminum, copper, thorium, manganese, uranium, cadmium, vanadium, niobium, tantalum, chromium, boron and titanium. A particularly suitable group of promoters includes the difiicultly soluble phosphates, molybdates, tungstates and selenates of the above metals, or the reduction products, containing oxygen, of such compounds, asfor example, th e/ corresponding selenites.

For purposes of control and economy, the/suitable base metal catalysts are employed whenever their use is feasible, however, it is to be understood that we may advantageously employ catalysts possessing the desired activity selected from the group comprising the noble metals such as silver, gold, platinum, palladium, osmium, ruthenium, rhodium, irridium and the like. We may also employ mixtures comprising one or more base metals with one or more noble metals.

A We have found that a very desirable pyrophoric nickel catalyst of great activity may be prepared by efiecting the reduction of thermaldecomposition of nickel salts of volatile organic acids. For example, a pyrophoric nickel catalyst particularly suitable for our purpose may be prepared by efsirable ressure.

fecting the reduction or decomposition of nickelous formate. The nickelous formate may be reduced by heating it to a temperature of from about 200 .C. to 350 C. in an atmosphere of hydrogen, or the nickelous formate may be dissolved or suspended in a suitable inert liquid such as a petroleum oil, a hydrocarbon and the like and the mixture heated to the decomposition temperature of the nickelous formate in the presence or absence of hydrogen or other suitable reducing gases.

The unsaturated alcohols may be treated severally or mixtures comprising a plurality of species of unsaturated alcohols may be hydrogenated without resorting to separation of the constituent alcohols. The unsaturated alcohols may in some cases be advantageously treated in the presence of suitable relatively inert substances. an unsaturated alcohol existing in the solid state at room temperature or the temperature at which hydrogenation is desired may be dissolved in a suitable solvent such as a hydrocarbon, alcohol, ether and the like. A suitable unsaturated alcohol may also be hydrogenated in the presence of an unsaturated compound which may or may not be also hydrogenated under the conditions of operation. We have found that, in general, the hydrogenationmay be advantageously eifected in the presence of substantial amounts of water. Accordingly, water-containing mixtures may be treated without resorting to costly drying opera-' tions. 7

The temperature at which our process may be effectively executed will be dependent upon the activity of the specific catalyst selected, upon the stability of the treated unsaturated alcohol with respect to its rearrangement, upon the contact time of the reactants and upon the effective pressure of hydrogen in the system. Due to the fact that the rearrangement of the unsaturated alcohols is usually accelerated at higher temperatures, we prefer to operate at temperatures not generally exceeding about 200 C. Higher temperatures may be employed in some cases if other factors such as contact time and pressure are adjusted and care is exercised to effect substantial hydrogenation while avoiding excessive rearrangement.

Although our invention is preferably executed with theunsaturated alcohol in the liquid phase, it is to be understood that vapor phase methods are also suitable, particularly with the more stable unsaturated alcohols when very active catalysts are employed.

The hydrogenation may be efiected at any de- In the majority of cases, moderately elevated pressures may be advantageously employed. The hydrogen may be utilized in a pure or substantially pure state or we may reveniently eifected in the'following manner. Anunsaturated alcohol of the type herein described,

For example,

distillation or other suitable means.

or a suitable mixture comprising such an alcohol, is charged to a suitable reaction vessel which is preferably equipped with means for agitating its contents as by mechanical stirring, and means for heating and cooling its contents. A selected catalyst, in the required amount, may be added to the reaction vessel in a suitable manner. When pyrophoric metal catalysts are used, the catalytic material is preferably added in such a manner that substantial exposure to the air is avoided. The hydrogen or hydrogen-containing gas is preferably added from a supply tank in communication with the reaction vessel, in an amount and at a'rate suil'lcient to maintain the desired pressure in the system. The rate of hydrogen absorption may be. materially accelerated by agitating. the contents of the reaction vessel while the hydrogen is being added.

The reaction, for the cases tested, was found to be exothermic. In many cases, and particularly when a pyrophoric metal catalyst is employed, the reaction may be initiated at room temperature; however, when necessary or desirable the same may be initiated at elevated temperatures. The conditions of operation may vary within certain limits as above described, the conditions being adjusted with respect to the catalyst and the unsaturated alcohol treated so as to permit the optimum rate of hydrogenation with the obviation of substantial rearrangement and/or decomposition of the unsaturated alcohol and the reaction product. The temperature. of the reaction mixture may be controlled by heating and/or cooling means and/or by regulating the rate of admittance and the pressure of the hydrogen in the system. If the heat supplied by the exothermicity of the reaction is not suflicient tomaintain the desired reaction temperature, we may resort to the use of external heating means.

When vapor phase methods'oi hydrogenation are resorted to, the unsaturated alcohol vapors in admixture with hydrogen, a suitable hydrogencontaining gas or a gaseous mixture or substance capable of liberating hydrogen under the conditions of operation, may be passed continuously at the desired space velocity over the catalytic material maintained at the desired temperature. The fluids discharged from the reaction vessel may be cooled and the condensed liquid conducted to a recovery stage wherein recovery or separation of the products and reactants may be effected by Any unrevacted unsaturated alcohol may be reutilized in the same or another hydrogenating unit.

For the'purpose of more clearly-illustrating preferred methods of executing our invention, ref

erence will be had to the following specific ex-.

amples.

Example I A pyrophoric nickel metal catalyst was prepared were charged to an iron reaction vessel and about 5 gm. of the nickel catalyst were added thereto. The contents of "the reaction vessel were vigorously agitated while hydrogen was applied at a gauge pressure of about 40 pounds per square inch.

The hydrogenation was initiated at room temperature. Afterthe reaction had started, the rate of hydrogenation rapidly increased, reaching a maximum when a conversion of about 90% had been effected. Beyond this degree of conversion the rate decrease-d until substantially complete hydrogenation was effected. The heat liberated due to the exothermicity of the reaction raised the reaction temperature to about 80 C.

The cooled reaction mixture was discharged from the reaction vessel and the catalyst separated therefrom by filtration. The filtrate was fractionated. The reaction product was'is obutyl alcohol which boiled at a temperature of about 107 C. at atmospheric pressure. The reaction mixture contained about 2% of isobutyraldehyde.

Example II About 3.95 gm. of the nickel catalyst were placed in a pyrex glass reaction tube, said reaction tube having a capacity of about 116 cc., and being enclosed in a suitable heating apparatus. Hydrogen and isobutenol, in admixture were passed over the catalyst at an average rate of about 370 cc. of hydrogen and 67.5 cc. (0.159 mol.) of isobutenol vapor per minute. The reaction was efiected at atemperature of about 150 C. and a pressure slightly greater than atmospheric.

The exit vapors were cooled and the condensed liquid fractionated. In about 6.75 hours, .78 cc. (63.1 gm.) of liquid reaction mixture was collected. This mixture contained isobutyl alcohol, 21.7% isobutenol, 1.67% isobutyraldehyde and 0.38% water. This data represents a conversion of 75% on one pass over the catalyst.

Example III The catalyst employed was finely divided nickel metal of pyrophoric character.

The hydrogenation was effected in the liquid phase in a steel autoclave having a capacity of about 3600 0c. The autoclave was provided with a mechanical stirrer and means for heating and cooling its contents.

About 2500 cc. of anhydrous isobutenol were charged to the autoclave and about 44 gm. of catalyst added. The hydrogen was introduced into the autoclave at a pressure of from about 200 to 300 lbs./sq. in. (gauge). The reaction started substantially as soon as the hydrogen was applied to the stirred contents of the autoclave. The heat liberated due to the occurrence of the hydrogenation reaction raised the temperature of the reaction mixture to about 150 C., which temperature was maintained substantially constant throughout the operation. When the hydrogenation no longer occurred at a practical rate, the hydrogen pressure was raised to and maintained at about 2000 lbs./sq. in. (gauge) for a short time.

This operation was executed in a total of six batches as above described. The same charge of nickel catalyst was used for all the batches. The hydrogenation of the first batch was initiated at room temperature, for the succeeding batches in initiation temperature of about 50 C. was required. The catalyst, after being used to hydrogenate six batches, failed to show any marked decrease in activity. v

Each batch of reaction product was cooled, discharged from the autoclave, the catalyst allowed to settle and the substantially clear liquid decanted therefrom. The separate batches of decanted liquor were mixed and the mixture filtered through diatomaceous earth to remove the suspended nickel. The filtrate (about 16 liters) was fractionated, the distillate being collected in two cuts as follows:

Cut I, which was collected in the boiling range of from C. to 106 C., represented 8%"by'vol ume of the still charge. Analysis Sh0wed t his cut to consist of 83% isobutyl alcohol, 11%water and 6% isobutyraldehyde by volume.

The second cut, which boiled in the rangeo f Example IV An active copper-iron catalyst was prepared in the following manner: A mixture consisting of about 400 gm. of crystalline ferric nitrate and about 77.4. gm. of cupric nitrate was placed in a quartz dish and heated until all the water was driven off and no more nitric oxide was evolved.

The residue was placed in a glass tube and the contents of the tube heated to a temperature of about 250 C. while a mixture consisting of equal parts of carbon monoxide and hydrogen was passed through it under atmospheric pressure. This treatment was continued until the reduction was substantially complete as indicated by the presence of hydrocarbons in the exit gas.

About'200 cc. (162 gm.) of isobutenol were charged to an autoclave provided with means for agitating and heating itscontents. A part of the copper-iron catalyst was transferred to thes autoclave under an inert atmosphere. The contents of the autoclave were vigorously agitated and heated while hydrogen was added under pressure. The hydrogenation reaction was initiated at temperatures below C. At C. the reaction proceeded at a practical rate, and at temperatures of C. and higher it proceeded very rapidly. At the higher temperatures, the reaction rate was relatively high at partial pressures of hydrogen as low as one atmosphere, while at temperatures of about 100 C. it was desirable lbs/sq. in. (gauge) in order to maintain a practical rate of reaction.

When hydrogen was no longer absorbed at an appreciable rate the operation was discontinued and the contents of the autoclave fractionated. About 80% of the theoretical amount of isobutyl alcohol was recovered by fractionation. Since mechanical losses and losses due to handling amounted to about 20%, the conversion of isobutenol to isobutyl alcohol was practically quantitative. There was no indication of rearrangement of the isobutenol to isobutyraldehyde.

The recovered isobutyl alcohol was substantial- 1y pure. It possessed a bromine number less than 0.18.

Example V Amixture consisting of primary and secondary iso-octenols was prepared by eifecting the hydrolysis of chlorinated diisobutylene. About 250 gm. of the mixture of iso-octenols were charged to an iron reaction vessel and about 5 gm. of a pyrophoric nickel catalyst prepared as described in Example I were added-thereto. The hydrogenation was eflected in the same manner as described in Example I.

When the reaction was substantially complete, the operation was terminated and the contents of the autoclave discharged and fractionated. The reaction product consisted of a substantially pure mixture of saturated primary and secondary iso-octyl alcohols.

to operate under total pressures of about 1100 Example VI About 200 cc. of methyl isopropenyl carbinol (cnFc-onon-cm) I were charged to an iron reaction vessel and about 2 grams of a pyrophoric nickel catalyst were added. The reaction vessel was agitated and heated while hydrogen was applied at a gauge pressure of about 500 lbs./sq. in. The hydrogenation was ature range of from 113.0 C. to 114 C. at atmospheric pressure. The bromine number of the product showed that it contained less than 1% of unchanged methyl isopropenyl carbinol.

v Emample'VII About 200 cc. of tiglyl alcohol (CHz-CH=C-CH OH) and about 2 gm. of a finely divided nickel catalyst were charged to an autoclave equipped with heating means and means for agitating its contents. The hydrogenation was-effected by agitating the contents of the autoclave and heating to a temperature of about (2., while hydrogen was added at a gauge pressure of about 500 lbs./sq. in. Hydrogen was added as required to maintain the pressure on the system. substantially constant. The hydrogenation was complete in about 2 hours.

At the end of this time the cooled contents of the autoclave were discharged therefrom and fractionated. The fractionation yielded about cc. of secondary butyl carbinol which boiled in the temperature range of from about l28.5 C. k

to about 129 C. under atmospheric pressure.

It will be evident that our invention may be executed with excellent results in a batch, inter-- mittent or continuous manner. When a mixture comprising a plurality of species of suitable unsaturated alcohols is hydrogenated, a reaction product consisting of a mixture of the corresponding saturated alcohols will be obtained. Such a mixture may be employed per se for any suitable'purpose or the various species of saturated and unsaturated alcohols may be separated by some suitable means such as distillation. While we have in the foregoing described in some detail the preferred embodiments of our invention and some variants thereof it will be understood that this is only for the purpose of making the invention more clear and that the invention is not to be regarded as limited to the details of operation described, nor is it dependent on the soundness or accuracy of the theories advanced as to the advantageous results attained. On the other hand, the invention is to be regarded as limited only by the terms of the accompanying claims, in which it is our intention to claim all noveltyinherent therein as broadly as possble in view of the prior art.

We claim as our invention:

1. A process for effecting the hydrogenation of the readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked by a single bond to a carbinol group which comprises reacting such an unsaturated'alcohol with hydrogen in the presence of a hydrogenation catalyst at a temperature below about 200 C.

2. A process for effecting the hydrogenation of the. readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked by a single bond to a carbinol group which comprises reacting such an unsaturated alcohol with hydrogen in the presence of a base metal catalyst at a temperature below about 200 C.

3. A process for efiecting the hydrogenation of the readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked by a single bond to a carbinol group which comprises reacting such an unsaturated alcohol with hydrogen in the presence of a base metal catalyst of pyrophoric character ata temperature below about 200 C.

4. A process for'effecting the hydrogenation of the readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked directly to a carbinol group which comprises reacting such an unsaturated alcohol with hydrogen in the presence of a pyrophoric metal catalyst of the class consisting of nickel, iron and cobalt at a temperature below about 200 C.

5. A process for efiecting the hydrogenation of the readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked directly to a carbinol group which comprises reacting such an unsaturated alcohol with hydrogen at a temperature below 200 C. and in the readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked directly to a secondary carbinol group which comprises reacting such an unsaturated alcohol with hydrogen in the presence of a pyrophoric metal catalyst of the class consisting of nickel, iron and cobalt at a temperature below about 200 C.

8. A process for efiecting the liquid phase hydrogenation of the readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked directly to a carbinol group which comprises reacting such an unsaturated alcohol with hydrogen in the presence of a 'pyrophoric metal catalyst of the class consisting of nickel, iron and cobalt at a temperature below about 200 C. I

9. A process for efiecting the liquid phase hydrogenation of the readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked directly to a carbinol group which comprises reacting such an unsaturated alcohol with hydrogen at an elevated tempei'ature but below 200 C. and in the presence of a pyrophoric metal catalyst of the class consisting of. nickel, iron and cobalt.

10. A process for effecting the \liquid phase hydrogenation of the readily rearrangeable unsaturated alcohols containing an unsaturated tertiary carbon atom linked directly to a carbinol group which comprises reacting such an unsaturated alcohol with hydrogen at a pressure greater than atmospheric and in the presence of a pyro- \phoric metal catalyst of the class consisting of nickel, iron and cobalt at a temperature below about 200 -C.

11. A process for effecting the liquid phase hydrogenation of a readily rearrangeable unsaturated alcohol containing an unsaturated tertiary carbon atom linked directly to a carbinol group which comprises reacting such an unsaturated alcohol With hydrogen in the presence of a pyrophoric nickel metal catalyst at a temperature below about 200 C.

12. A process for effecting the hydrogenation of isopentenol possessing an unsaturated tertiary carbon atom linked to a carbinolgroup which comprises reacting such isopentenol with hydrogen in the presence of a pyrophoric metal catalyst of the class consisting of nickel, iron and cobalt at a temperature below about 200 C.

13. A process for efiecting the liquid phase hydrogenation of isopentenol containing an unsaturated tertiary carbon atom linked to a carbimetal catalyst of the class consisting of nickel,

iron and cobalt at a temperature below about 200 C.

15. A process for'effecting the liquid phase hydrogenation of isobutenol which comprises reacting isobutenol with hydrogen in the presence of a pyrophoric nickel metal catalyst at a temperature below about 200 C.

HERBERT P. A. GROLL. JAMES BURGIN. 

